Social and Behavioral Sciences Commons^™

The Arctic Research Of The Composition Of The Troposphere From Aircraft And Satellites (Arctas) Mission: Design, Execution, And First Results, D J. Jacob, J H. Crawford, H Maring, A D. Clarke, J E. Dibb, L K. Emmons, R A. Ferrare, C A. Hostetler, P B. Russell, H B. Singh, A M. Thompson, G E. Shaw, E Mccauley, J R. Pederson, J A. Fisher

Jenny A Fisher

The NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) mission was conducted in two 3-week deployments based in Alaska (April 2008) and western Canada (June–July 2008). Its goal was to better understand the factors driving current changes in Arctic atmospheric composition and climate, including (1) influx of mid-latitude pollution, (2) boreal forest fires, (3) aerosol radiative forcing, and (4) chemical processes. The June–July deployment was preceded by one week of flights over California (ARCTAS-CARB) focused on (1) improving state emission inventories for greenhouse gases and aerosols, (2) providing observations to test and improve models …

Sources, Distribution, And Acidity Of Sulfate-Ammonium Aerosol In The Arctic In Winter-Spring, Jenny A. Fisher, Daniel J. Jacob, Q Wang, Roya Bahreini, C C. Carouge, M J. Cubison, Jack E. Dibb, Thomas Diehl, J L. Jimenez, E M. Leibensperger, Zifeng Lu, Marcel B.J Meinders, H. O T. Pye, Patricia K. Quinn, Sangeeta Sharma, David G. Streets, Aaron Van Donkelaar, R M. Yantosca

Jenny A Fisher

We use GEOS-Chem chemical transport model simulations of sulfate–ammonium aerosol data from the NASA ARCTAS and NOAA ARCPAC aircraft campaigns in the North American Arctic in April 2008, together with longer-term data from surface sites, to better understand aerosol sources in the Arctic in winter–spring and the implications for aerosol acidity. Arctic pollution is dominated by transport from mid-latitudes, and we test the relevant ammonia and sulfur dioxide emission inventories in the model by comparison with wet deposition flux data over the source continents. We find that a complicated mix of natural and anthropogenic sources with different vertical signatures is …

Factors Driving Mercury Variability In The Arctic Atmosphere And Ocean Over The Past 30 Years, Jenny A. Fisher, Daniel J. Jacob, Anne L. Soerensen, Helen M. Amos, Elizabeth S. Corbitt, David G. Streets, Qiaoqiao Wang, Robert M. Yantosca, Elsie M. Sunderland

Jenny A Fisher

[1] Long-term observations at Arctic sites (Alert and Zeppelin) show large interannual variability (IAV) in atmospheric mercury (Hg), implying a strong sensitivity of Hg to environmental factors and potentially to climate change. We use the GEOS-Chem global biogeochemical Hg model to interpret these observations and identify the principal drivers of spring and summer IAV in the Arctic atmosphere and surface ocean from 1979–2008. The model has moderate skill in simulating the observed atmospheric IAV at the two sites (r ~ 0.4) and successfully reproduces a long-term shift at Alert in the timing of the spring minimum from May to April …

Riverine Source Of Arctic Ocean Mercury Inferred From Atmospheric Observations, Jenny A. Fisher, Daniel J. Jacob, Anne L. Soerensen, Helen M. Amos, Alexandra Steffen, Elsie M. Sunderland

Jenny A Fisher

Methylmercury is a potent neurotoxin that accumulates in aquatic food webs. Human activities, including industry and mining, have increased inorganic mercury inputs to terrestrial and aquatic ecosystems. Methylation of this mercury generates methylmercury, and is thus a public health concern. Marine methylmercury is a particular concern in the Arctic, where indigenous peoples rely heavily on marine-based diets. In the summer, atmospheric inorganic mercury concentrations peak in the Arctic, whereas they reach a minimum in the northern mid-latitudes. Here, we use a global three-dimensional ocean–atmosphere model to examine the cause of this Arctic summertime maximum. According to our simulations, circumpolar rivers …

Sources Of Carbonaceous Aerosols And Deposited Black Carbon In The Arctic In Winter-Spring: Implications For Radiative Forcing, Q Wang, D J. Jacob, J A. Fisher, J Mao, E M. Leibensperger, C C. Carouge, P Le Sager, Y Kondo, J L. Jimenez, M J. Cubison, S J. Doherty

Jenny A Fisher

We use a global chemical transport model (GEOS-Chem CTM) to interpret observations of black carbon (BC) and organic aerosol (OA) from the NASA ARCTAS aircraft campaign over the North American Arctic in April 2008, as well as longer-term records in surface air and in snow (2007-2009). BC emission inventories for North America, Europe, and Asia in the model are tested by comparison with surface air observations over these source regions. Russian open fires were the dominant source of OA in the Arctic troposphere during ARCTAS but we find that BC was of prevailingly anthropogenic (fossil fuel and biofuel) origin, particularly …

Chemistry Of Hydrogen Oxide Radicals (Hox) In The Arctic Troposphere In Spring, J Mao, D J. Jacob, M J. Evans, J R. Olson, X Ren, W H. Brune, T M. St. Clair, J D. Crounse, K M. Spencer, M R. Beaver, P O. Wennberg, M J. Cubison, J L. Jimenez, A Fried, P Weibring, J G. Walega, S R. Hall, A J. Weinheimer, R C. Cohen, G Chen, J H. Crawford, C Mcnaughton, A D. Clarke, L Jaegle, Jenny A. Fisher, R M. Yantosca, P Le Sager, C C. Carouge

Jenny A Fisher

We use observations from the April 2008 NASA ARCTAS aircraft campaign to the North American Arctic, interpreted with a global 3-D chemical transport model (GEOS-Chem), to better understand the sources and cycling of hydrogen oxide radicals (HOx≡H+OH+peroxy radicals) and their reservoirs (HOy≡HOx+peroxides) in the springtime Arctic atmosphere. We find that a standard gas-phase chemical mechanism overestimates the observed HO2 and H2O2 concentrations. Computation of HOx and HOy gas-phase chemical budgets on the basis of the aircraft observations also indicates a large missing sink for both. We hypothesize that this could reflect HO2 uptake by aerosols, favored by low temperatures and …

Source Attribution And Interannual Variability Of Arctic Pollution In Spring Constrained By Aircraft (Arctas, Arcpac) And Satellite (Airs) Observations Of Carbon Monoxide, J A. Fisher, D J. Jacob, M T. Purdy, M Kopacz, P Le Sager, C C. Carouge, C D. Holmes, R M. Yantosca, R L. Batchelor, K Strong, G S. Diskin, H E. Fuelberg, J S. Holloway, E J. Hyer, W. W Mcmillan, J Warner, D G. Streets, Q Zhang, Y Yang, S Wu

Jenny A Fisher

We use aircraft observations of carbon monoxide (CO) from the NASA ARCTAS and NOAA ARCPAC campaigns in April 2008 together with multiyear (2003– 2008) CO satellite data from the AIRS instrument and a global chemical transport model (GEOS-Chem) to better understand the sources, transport, and interannual variability of pollution in the Arctic in spring. Model simulation of the aircraft data gives best estimates of CO emissions in April 2008 of 26 Tg month−1 for Asian anthropogenic, 9.4 for European anthropogenic, 4.1 for North American anthropogenic, 15 for Russian biomass burning (anomalously large that year), and 23 for Southeast Asian biomass …

First Occurrence And Biogeographical Significance Of The Operculate Tetracoral Goniophyllum From The Wenlock (Silurian) Of Baillie-Hamilton Island, Canadian Arctic, Anthony J. Wright

Anthony Wright

Opercula of the Silurian tetracoral genera Goniophyllum and Rhizophyllum are described from early Wenlock (Sheinwoodian) strata of the Cape Phillips Formation, Baillie-Hamilton Island, Canadian Arctic. This is the first record of Goniophyllum in northern Laurentia, emphasising previously recognised faunal connections of this region with Baltica and Avalonia. As the opercula of Goniophyllum belong mostly to very early juveniles, which have not previously been documented, specific identification is impossible.

Responses Of Plants In Polar Regions To Uvb Exposure : A Meta-Analysis, K. K. Newsham, Sharon A. Robinson

Sharon Robinson

We report a meta-analysis of data from 34 field studies into the effects of UV-B radiation on Arctic and Antarctic bryophytes and angiosperms. The studies measured plant responses to decreases in UV-B radiation under screens, natural fluctuations in UV-B irradiance, or increases in UV-B radiation applied from fluorescent UV lamps. Exposure to UV-B radiation was found to increase the concentrations of UV-B absorbing compounds in leaves or thalli by 7% and 25% (expressed on a mass or area basis, respectively). UV-B exposure also reduced aboveground biomass and plant height by 15% and 10%, respectively, and increased DNA damage by 90%. …

Canada And Russia In The North Pole: Cooperation, Conflict, And Canadian Identity In The Interpretation Of The Arctic Region, Nick J. Sciullo

Nick J. Sciullo

The Arctic debate touches on a number of important international issues: national security, energy exploration and policy, environmental concerns, and maritime commerce are but a few. The North Pole, the Arctic more generally, is becoming increasingly important to a number of international actors as climate change causes ice to melt and the Arctic's waters become increasingly navigable. The pressure to lay claim to the Canadian North is intense, as countries clamor for the right to firmly plant their flags and lay the foundations for their military bases and research facilities.

Canadians must confront threats to sovereignty that they have not …